This snippet shows how to read parameters from Java Mapping in SAP PI

ReadParameter.java

public void transform(TransformationInput arg0, TransformationOutput arg1) throws StreamTransformationException 
{
	try{
		String Parameter1 = arg0.getInputParameters().getString("PARAM1");
		String Parameter2 = arg0.getInputParameters().getString("PARAM2");
		String Parameter3 = arg0.getInputParameters().getString("PARAM3");
		OutputStream out = (OutputStream) arg1.getOutputPayload().getOutputStream();
		out.write( ("PARAM1 = " + Parameter1 + "\r\n").getBytes() );
		out.write( ("PARAM2 = " + Parameter2 + "\r\n").getBytes() );
		out.write( ("PARAM3 = " + Parameter3 + "\r\n").getBytes() );
	}catch(Exception ee){
		throw new StreamTransformationException("Error while reading the parameterized mapping.".concat(ee.getMessage()));
	}
}